Display device with touch panel

ABSTRACT

A touch panel includes a substrate, a plurality of first electrodes extending in a first direction on the substrate and being disposed in parallel in a second direction intersecting the first direction, and a plurality of second electrodes intersecting the plurality of first electrodes, extending in the second direction, and being disposed in parallel in the first direction. Each of the plurality of first electrodes includes a first portion and a second portion with the second portion of first electrode and the second electrode being made of a first conductive film, and the first portion of the first electrode being made of a second conductive film.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. application Ser. No.13/798,372, filed Mar. 13, 2013, now U.S. Pat. No. 8,643,627, which is acontinuation of U.S. application Ser. No. 12/427,878, filed Apr. 22,2009, now U.S. Pat. No. 8,436,830, the contents of which areincorporated herein by reference.

The present application claims priority from Japanese application JP2008-111414 filed on Apr. 22, 2008, the content of which is herebyincorporated by reference into this application.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a display device with a touch panel,and more particularly, to a display device with a touch panel whichincludes a capacitance coupling type touch panel.

2. Description of the Related Art

Major systems adopted by conventional touch panels include a system ofdetecting an optical change and a system of detecting a change inelectric characteristic. As systems of detecting a change in electriccharacteristic, a capacitance coupling system is known (see, forexample, JP 2008-65748 A and JP 2009-015489 A).

FIGS. 9 to 11 illustrate a conventional capacitance coupling type touchpanel. FIG. 9 is a plan diagram illustrating an electrode pattern, FIG.10 is a sectional diagram illustrating a sectional structure cut on theline X-X of FIG. 9, and FIG. 11 is a sectional diagram illustrating asectional structure cut on the line XI-XI of FIG. 9.

As illustrated in FIGS. 9 to 11, the conventional capacitance couplingtype touch panel includes a plurality of electrodes 1X extending in afirst direction (e.g., X direction) and being disposed in parallel in asecond direction (e.g., Y direction) intersecting the first direction,and a plurality of electrodes 2Y intersecting the electrodes 1X,extending in the second direction, and being disposed in parallel in thefirst direction. The plurality of electrodes 2Y are disposed on asubstrate 11 to be covered with an insulating film 12 formed thereon.The plurality of electrodes 1X are disposed on the insulating film 12 tobe covered with a protective film 13 formed thereon. The electrodes 1Xand 2Y are made of transparent conductive materials such as indium tinoxides (ITOs).

In the conventional capacitance coupling type touch panel, asillustrated in FIGS. 9 to 11, the plurality of electrodes 1X and theplurality of electrodes 2Y are formed on different conductive layers(upper and lower layers) via the insulating film 12. In the case of thiselectrode structure, distortion occurs in the protective film 13 formedon the insulating film 12 and the electrodes 1X of the upper layerbecause of the electrode 1X of the upper layer, and optical path lengthsare different between the upper and lower layers with respect to areflected light. Thus, a color difference is generated between the upperelectrodes 1X and the lower electrodes 2Y, making electrode patterns ofthe electrodes 1X and 2Y visible. Such visible electrode patterns causedeterioration of optical characteristics and reduction incharacteristics of a display device incorporating the touch panel. Thus,countermeasures are necessary.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a technology capableof suppressing reduction in characteristics of a display device with atouch panel.

This and other objects and novel features of the present inventionbecome apparent upon reading of the detailed description of theinvention in conjunction with the accompanying drawings.

A typical aspect of the invention disclosed in this application isbriefly outlined as follows.

(1) A display device with a touch panel includes: a display panel; and acapacitance coupling type touch panel disposed on a surface of anobserver side of the display panel, in which: the capacitance couplingtype touch panel includes on a substrate, a plurality of firstelectrodes extending in a first direction and being disposed in parallelin a second direction intersecting the first direction, and a pluralityof second electrodes intersecting the plurality of first electrodes,extending in the second direction, and being disposed in parallel in thefirst direction; each of the plurality of first electrodes includes afirst portion formed on a layer different from a layer of the pluralityof second electrodes to intersect one of the plurality of secondelectrodes, and a second portion formed on the same layer as the layerof the plurality of second electrodes separately from the plurality ofsecond electrodes; and the first portion is connected to the secondportion via a contact hole formed through an insulating film formedbetween the first portion and the plurality of second electrodes.

(2) In the display device with the touch panel according to item (1),the first portion of the plurality of first electrodes is formed abovethe plurality of second electrodes.

(3) In the display device with the touch panel according to item (1),the first portion of the plurality of first electrodes is formed belowthe plurality of second electrodes.

(4) In the display device with the touch panel according to any one ofitems (1) to (3), each of the plurality of second electrodes includes aportion wider than a portion intersecting the plurality of firstelectrodes between the plurality of first electrodes; and the each ofthe plurality of first electrodes includes a portion wider than aportion intersecting the plurality of second electrodes between theplurality of second electrodes.

(5) In the display device with the touch panel according to any one ofitems (1) to (4), the plurality of first electrodes and the plurality ofsecond electrodes are made of transparent conductive materials.

(6) The display device with the touch panel according to any one ofitems (1) to (5) further includes a protective film formed on thesubstrate to cover the plurality of first electrodes and the pluralityof second electrodes.

The present invention enables suppression of reduction incharacteristics of the display device with the touch panel.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings:

FIG. 1 is a plan diagram illustrating electrode patterns of a touchpanel incorporated in a display device with a touch panel according to afirst embodiment of the present invention;

FIG. 2 is an enlarged plan diagram of a part of FIG. 1;

FIG. 3 is a sectional diagram illustrating a sectional structure cut onthe line III-III of FIG. 1;

FIG. 4 is a sectional diagram illustrating a sectional structure cut onthe line IV-IV of FIG. 1;

FIG. 5 is a block diagram illustrating a schematic configuration of thedisplay device with the touch panel according to the first embodiment ofthe present invention;

FIG. 6 is a plan diagram illustrating electrode patterns of a touchpanel incorporated in a display device with a touch panel according to asecond embodiment of the present invention;

FIG. 7 is a sectional diagram illustrating a sectional structure cut onthe line VII-VII of FIG. 6;

FIG. 8 is a sectional diagram illustrating a sectional structure cut onthe line VIII-VIII of FIG. 6;

FIG. 9 is a plan diagram illustrating electrode patterns of aconventional capacitance coupling type touch panel;

FIG. 10 is a sectional diagram illustrating a sectional structure cut onthe line X-X of FIG. 9; and

FIG. 11 is a sectional diagram illustrating a sectional structure cut onthe line XI-XI of FIG. 9.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, referring to the drawings, embodiments of the presentinvention are described in detail. Throughout the drawings illustrativeof the embodiments of the present invention, similar functions aredenoted by similar reference numerals and symbols, and repeateddescription thereof is avoided.

First Embodiment

A first embodiment of the present invention is described by way ofexample in which the present invention is applied to a display devicewith a touch panel, which includes the touch panel on a display panelsuch as a liquid crystal display panel.

FIGS. 1 to 5 illustrate the display device with the touch panelaccording to the first embodiment of the present invention:

FIG. 1 is a plan diagram illustrating electrode patterns of a touchpanel incorporated in the display device with the touch panel;

FIG. 2 is an enlarged plan diagram of a part of FIG. 1;

FIG. 3 is a sectional diagram illustrating a sectional structure cut onthe line III-III of FIG. 1;

FIG. 4 is a sectional diagram illustrating a sectional structure cut onthe line IV-IV of FIG. 1; and

FIG. 5 is a block diagram illustrating a schematic configuration of thedisplay device with the touch panel.

In FIG. 5, a touch panel 20 illustrates a sectional structure cut on theline V-V of FIG. 1.

As illustrated in FIG. 5, the display device with the touch panel of thefirst embodiment includes a liquid crystal display panel 30, thecapacitance coupling type touch panel 20 disposed on a surface of anobserver side of the liquid crystal display panel 30, and a backlight 40disposed below a surface opposed to the observer side of the liquidcrystal display panel 30. For the liquid crystal display panel 30, forexample, a liquid crystal display panel of an in-plane switching (IPS)type, a twisted nematic (TN) type or a vertical alignment (VA) type isused.

As illustrated in FIGS. 1 to 4, the touch panel 20 includes a pluralityof electrodes 1X extending in a first direction (e.g., X direction) andbeing disposed in parallel at predetermined array pitches in a seconddirection (e.g., Y direction) intersecting the first direction, and aplurality of electrodes 2Y intersecting the electrodes 1X, extending inthe second direction, and being disposed in parallel at predeterminedarray pitches in the first direction.

The plurality of electrodes 2Y are each formed with an electrode patternin which a plurality of first portions 2 a and a plurality of secondportions 2 b wider than the first portions 2 a are alternately arrangedin the second direction. The plurality of electrodes 2Y are eachdisposed on a surface of an observer side of a substrate 11 to becovered with an insulating film 12 formed thereon. For the substrate 11,a transparent insulating substrate such as glass is used.

The plurality of electrodes 1X are each formed with an electrode patternin which a plurality of first portions 1 a and a plurality of secondportions 1 b wider than the first portions 1 a are alternately arrangedin the first direction. Each of the first portions 1 a of the pluralityof electrodes 1X is formed on a conductive layer different from that ofthe electrode 2Y to intersect the first portion 2 a of the electrode 2Yin a planar manner. Each of the second portions 1 b of the plurality ofelectrodes 1X is formed on the same conductive layer as that of theelectrode 2Y separately from the electrode 2Y. In this embodiment, thefirst portion 1 a of the electrode 1X is formed above the electrode 2Y.

Each of the second portions 1 b of the plurality of electrodes 1X iscovered with the insulating film 12 as in the case of the electrodes 2Y.Each of the first portions 1 a of the plurality of electrodes 1X isdisposed on the insulating film 12 to be covered with a protective layer13 formed thereon.

The first portion 1 a of the electrode 1X intersects the first portion 2a of the electrode 2Y in a planar manner, and is electrically andmechanically connected to two adjacent second portions 1 b sandwichingthe first portion 2 a via a contact hole 12 a formed through theinsulating film 12 which is an interlayer insulating film between thefirst portion 1 a of the electrode 1X and the electrode 2Y.

In other words, each of the plurality of electrodes 1X includes a firstportion 1 a formed on a conductive layer different from that of theelectrode 2Y to intersect the electrode 2Y, and a second portion 1 bformed on the same conductive layer as that of the electrode 2Yseparately from the electrode 2Y. The first portion 1 a of the electrode1X is connected to the second portion 1 b of the electrode 1X via thecontact hole 12 a formed through the insulating film 12 between thefirst portion 1 a and the electrode 2Y.

The second portion 2 b of the electrode 2Y is disposed between the firstportions 1 a in the two adjacent electrodes 1X in a plan view. Thesecond portion 1 b of the electrode 1X is disposed between the firstportions 2 a in the two adjacent electrodes 2Y in a plan view.

In other words, the electrode 2Y has a portion wider than that of aportion intersecting the electrode 1X between the electrode 2Y and theelectrode 1X. The electrode 1X has a portion wider than that of aportion intersecting the electrode 2Y between the electrode 1X and theelectrode 2Y.

The electrodes 1X and 2Y are made of highly transmissive materials, forexample, transparent conductive materials such as indium tin oxides(ITOs).

FIG. 5 schematically illustrates capacities C1 and C3 between anobserver's finger 50 and the electrode 1X and a capacity C2 between theobserver's finger 50 and the electrode 2Y. The touch panel 20 of thisembodiment detects a capacity difference of coupled capacities betweenthe electrodes 1X and 2Y to detect touch position coordinates in a touchsurface of the touch panel 20 touched by the observer's finger 50.

Referring to FIGS. 1 to 4, a manufacturing method for the touch panel 20of this embodiment is described.

First, a first conductive film made of a transparent conductive material(e.g., ITO) is formed on the surface of the observer side of thesubstrate 11.

A first mask for the electrode pattern is formed on the first conductivefilm by using, for example, a positive resist. Then, the firstconductive film is etched by using the first mask as an etching mask toform the electrode 2Y and the second portion 1 b of the electrode 1X.

The first mask is removed, and the insulating film 12 made of, forexample, a negative resist, is formed on the substrate 11 and on theelectrode 2Y and the second portion 1 b of the electrode 1X. In thisstep, the electrode 2Y and the second portion 1 b of the electrode 1Xare covered with the insulating film 12.

The contact hole 12 a is formed in a necessary part of the insulatingfilm 12. A second conductive film made of a transparent conductivematerial (e.g., ITO) is formed on the insulating film 12 and in thecontact hole 12 a.

A second mask for the electrode pattern is formed on the secondconductive film by using, for example, a positive resist. Then, thesecond conductive film is etched by using the second mask as an etchingmask to form the first portion 1 a of the electrode 1X on the insulatingfilm 12. In this step, the first portion 1 a of the upper layer iselectrically and mechanically connected to the second portion 1 b of thelower layer via the contact hole 12 a. The first portion 1 a of theupper layer intersects the first portion 1 a of the electrode 2Y of thelower layer.

Next, the second mask is removed, and the protective film 13 made of,for example, a negative resist, is formed on the insulating film 12 andon the first portion 1 a of the electrode 1X, thereby forming astructure illustrated in FIGS. 1 to 4. In this step, the first portion 1a of the electrode 1X is covered with the protective film 13.

Formation of peripheral wiring line patterns can be inserted in anappropriate place among the steps.

In a conventional capacitance coupling type touch panel, as illustratedin FIGS. 9 to 11, a plurality of electrodes 1X and a plurality ofelectrodes 2Y are formed on different conductive layers (lower and upperlayers) via an insulating film 12. In the case of this electrodestructure, distortion occurs in a protective film 13 formed on theinsulating film 12 and the electrode 1X of the upper layer due to theelectrode 1X of the upper layer, and optical path lengths are differentbetween the lower and upper layers with respect to a reflected light.Thus, a color difference is generated between the electrode 2Y of thelower layer and the electrode 1X of the upper layer, making electrodepatterns of the electrodes 1X and 2Y visible.

On the other hand, in the capacitance coupling type touch panel 20 ofthis embodiment, as illustrated in FIGS. 1 to 4, the electrode 1Xincludes the first portion 1 a formed on the layer different from thatof the electrode 2Y to intersect the electrode 2Y, and the secondportion 1 b formed on the same layer as that of the electrode 2Yseparately from the electrode 2Y. The first portion 1 a is connected tothe second portion 1 b via the contact hole 12 a formed through theinsulating film 12 between the first portion 1 a and the electrode 2Y.

In the case of this electrode structure, the protective film 13 can beformed to be uniform, enabling suppression of distortion of theprotective film 13 and visualization of the electrode patterns caused bya color difference due to the distortion of the protective film 13. As aresult, deterioration of optical characteristics caused by visualizationof the electrode patterns can be suppressed, and hence reduction incharacteristics of the display device incorporating the touch panel 20can be suppressed.

Portions in which color differences are generated can be reduced to aminimum, in other words, to only the first portion 1 a of the electrode1X, and hence visualization of electrode patterns caused by a colordifference generated due to an optical path difference can also besuppressed. As a result, deterioration of optical characteristics causedby visualization of the electrode patterns can be suppressed, and hencereduction in characteristics of the display device incorporating thetouch panel 20 can be suppressed.

When a defect occurs in the first portion 1 a (bridge portion) formed onthe upper layer, the defect can be repaired by re-executing the step offorming the first portion 1 a, and deterioration of opticalcharacteristics caused by visualization of the electrode patterns can besuppressed to improve processing performance.

Second Embodiment

FIGS. 6 to 8 illustrate a display device with a touch panel according toa second embodiment of the present invention:

FIG. 6 is a plan diagram illustrating electrode patterns of a touchpanel incorporated in the display device with the touch panel;

FIG. 7 is a sectional diagram illustrating a sectional structure cut onthe line VII-VII of FIG. 6; and

FIG. 8 is a sectional diagram illustrating a sectional structure cut onthe line VIII-VIII of FIG. 6.

The display device with the touch panel of the second embodiment isbasically similar in configuration to that of the first embodiment, andis different as follows.

In the first embodiment, as illustrated in FIGS. 1 to 4, the electrode2Y and the second portion 1 b of the electrode 1X are formed on thelower conductive layer, and the first portion 1 a of the electrode 1X isformed on the upper conductive layer. In the second embodiment, however,as illustrated in FIGS. 6 to 8, a first portion 1 a of an electrode 1Xis formed on a lower conductive layer, and an electrode 2Y and a secondportion 1 b of an electrode 1X are formed on an upper conductive layer.

The first portion 1 a (lower layer in this embodiment) of the electrode1X intersects a first portion 2 a of the electrode 2Y, and iselectrically and mechanically connected to two adjacent second portions1 b (upper layer in this embodiment) sandwiching the first portion 2 avia a contact hole 12 a formed through an insulating film 12 which is aninterlayer insulating film between the first portion 1 a of theelectrode 1X and the electrode 2Y.

Also in the second embodiment, visualization of electrode patternscaused by a color difference due to distortion of a protective film 13and visualization of electrode patterns caused by a color difference dueto an optical path difference can be suppressed. Thus, deterioration ofoptical characteristics caused by visualization of the electrodepatterns can be suppressed, and reduction in characteristics of thedisplay device incorporating the touch panel 20 can be suppressed.

The above-mentioned embodiments have been directed to the display devicewith the touch panel, which includes the touch panel on the liquidcrystal display panel as an example of the display panel. However, thepresent invention is not limited to this. The present invention can beapplied to a display device with a touch panel which includes the touchpanel on another display panel such as an organic EL display panel or aninorganic EL display panel.

The invention which has been made by the inventors of the presentinvention has specifically been described based on the embodiments. Notlimited to the embodiments, however, various changes and modificationscan be made without departing from the gist of the invention.

What is claimed is:
 1. A touch panel comprising: a substrate, aplurality of first electrodes extending in a first direction on thesubstrate and being disposed in parallel in a second directionintersecting the first direction, and a plurality of second electrodesintersecting the plurality of first electrodes, extending in the seconddirection, and being disposed in parallel in the first direction;wherein each of the plurality of first electrodes includes a firstportion and a second portion; wherein the second portion of firstelectrode and the second electrode are made of a first conductive film,and the first portion of the first electrode is made of a secondconductive film; wherein an insulating film which is made of negativeresist is formed between the first conductive film and the secondconductive film, wherein a contact portion which is formed above thesecond portion of the first electrode is exposed by removal of theinsulating film, wherein the insulating film includes an interlayerportion which is formed at an intersection of the first portion of thefirst electrode and the second electrode, and wherein the first portionof the first electrode is formed above the interlayer portion andelectrically connects between two adjacent contact portions.
 2. A touchpanel according to claim 1, wherein the first portion of the firstelectrode is formed above the plurality of second electrodes.
 3. A touchpanel according to claim 1, wherein the second portion of the firstelectrode is a square electrode, the contact portion is formed at acorner of the square electrode.
 4. A touch panel according to claim 1,wherein: each of the plurality of second electrodes includes a portionwider than a portion intersecting the first portion of the firstelectrode, between adjacent two electrodes of the plurality of firstelectrodes.
 5. A touch panel according to claim 1, wherein the pluralityof first electrodes and the plurality of second electrodes are made oftransparent conductive materials.
 6. A touch panel according to claim 1,further comprising a protective film formed on the substrate to coverthe plurality of first electrodes and the plurality of secondelectrodes.
 7. A touch panel comprising: a substrate; a plurality offirst electrodes extending in a first direction on the substrate, and aplurality of second electrodes intersecting the plurality of firstelectrodes; wherein each of the plurality of first electrodes includes afirst portion and a second portion; wherein the second portion of firstelectrode and the second electrode are made of a first conductive layer;wherein the first portion of the first electrode is made of a secondconductive layer; wherein the second portion of the first electrode is asquare electrode; wherein an insulating film which is made of negativeresist is formed between the first conductive layer and the secondconductive layer; wherein a contact portion which is formed above thesecond portion of the first electrode is formed at a corner of thesquare electrode; wherein the insulating film includes an interlayerportion which is formed at an intersection of the first portion of thefirst electrode and the second electrode; and wherein the first portionof the first electrode is formed above the interlayer portion andelectrically connects between two adjacent contact portions.
 8. A touchpanel according to claim 7, wherein the first portion of the firstelectrode is formed above the plurality of second electrodes.
 9. A touchpanel according to claim 7, wherein each of the plurality of secondelectrodes includes a portion wider than a portion intersecting thefirst portion of the first electrode, between adjacent two electrodes ofthe plurality of first electrodes.
 10. A touch panel according to claim7, wherein each of the plurality of first electrodes includes the secondportion of the first electrode being larger in width than a width of thefirst portion of the first electrode, between adjacent two electrodes ofthe plurality of second electrodes.
 11. A touch panel according to claim7, wherein the plurality of first electrodes and the plurality of secondelectrodes are made of transparent conductive materials.
 12. A touchpanel according to claim 7, further comprising a protective film formedon the substrate to cover the plurality of first electrodes and theplurality of second electrodes.